1. Field of the Invention
This invention relates to methods for preparing a protein-enriched soluble fiber composition and the use of this material in making a dietary supplement.
2. Related Art
The soluble fiber useful according to the subject invention is well known to those skilled in this art. Specifically exemplified herein is the use of pectin and guar gum compositions as the soluble fiber source. Pectins are a group of high-molecular-weight heterogenous polysaccharides which serve as fundamental structural components of plant cell walls in fruits and vegetables, particularly limes, lemons, grapefruit, and oranges. Pectin is composed of D-anhydrogalacturonic acid units linked through .alpha.(1.fwdarw.4)-glycosidic bonds forming a polygalacturonic acid with some of the carboxyl groups esterified with methanol. Since pectin and guar gum are not susceptible to hydrolysis by the alimentary tract enzymes of humans, it is classified as a water-soluble fiber dietary supplement.
Soluble fiber products are often manufactured by aqueous extraction of appropriate edible plant material such as those enumerated above. Several specific examples are discussed below.
Guar gum. Guar gum is derived from the seed of the guar plant. The plant has been grown in India and Pakistan for centuries. The guar plant is a pod-bearing legume. The seeds of the plant are composed of the hull, germ, and endosperm. Guar gum is produced by milling the endosperm after removal of the hull and germ.
Guar gum, which has a molecular weight of about 220,000-300,000, is a galactomannan with linear chains of D-galactomannopyranosyl units with side branching units of D-galactopyranose attached by (1.fwdarw.6) linkages.
Guar gum is nonionic and is compatible with salts over a wide range of electrolyte concentration. The hydration and water-binding properties of guar gum are responsible for its use in food stabilization systems. Ice cream stabilizers, particularly high-temperature, short-time processes, use guar gum, at a concentration of 0.3%. These same properties render it useful in the stabilization of ice pops and sherbets. Guar is allowed at levels up to 3.0% in cold-pack cheese foods. In soft cheeses, guar increases the yield of curd solids and gives curds a better texture. It is useful in cake and donut mixes at levels under 1%. In pie fillings, guar thickens and prevents shrinking and cracking of the filling. Used in icings to absorb free water, guar gum is mixed at a level of 1 part gum to 250 parts sugar and 30 parts water.
Guar gum has also been used as a thickener in salad dressings and pickle and relish sauces at 0.2-0.8%. Gum guar alone or in combination with agar at levels of 0.5% is useful in processing canned meat products. It prevents fat migration during storage and stops syneresis and water accumulation and reduces the tendency for voids to be present in the can.
Locust bean gum. The locust bean, or carob, is an ancient leguminous plant. It is indigenous to the Mediterranean and Near East. Arabs used the carob seed as a unit of weight. The seed, called karat, became a standard (carats) against which gold and precious gems were weighed. The carob pod or fruit has been widely used as a foodstuff. It is very sweet, and its flavor is further enhanced by roasting. The carob fruit is dark brown, 4-10 inches long, and pod-like. The pod contains the seed which is the source of locust bean gum. The seed is composed of the outer husk, a central germ, and the endosperm. The semitransparent layer of endosperm yields the desired gum. In commerce the seed is dehusked, split, and the germ removed. The separated endosperm is finely milled. The gum is an off-white powder.
Locust bean gum, which has a molecular weight of 310,000, is essentially a straight D-mannose polymer with branching on every fourth or fifth mannose group on C-6 by single D-galactose units. The structure is similar to that of gum guar.
Locust bean gum is widely used today in many industries. It is an excellent ice cream stabilizer. Carob bean gum acts as a binder and stabilizer in processed meats, salami, bologna, and pork sausages. In soft cheese manufacture, about 0.5% locust bean gum speeds up coagulation, increases the yield of curd solids by about 10%, and makes the curd easier to separate and remove. Locust bean gum is sometimes used to thicken soups at levels of 0.2-0.5%. Locust bean gum is used as a thickener in pie fillings. The gum yields a clear, fruit-like filling when used at a level of 1-2% of the weight of the fruit juice and water. In bakery products the use of high quality locust bean gum produces more uniform doughs. Locust bean gum is utilized as a stabilizer and binder in many prepared foods such as soup bases, sauces, frozen batter, and vegetable and fish dishes. IT has been used to stabilized whipped cream, mayonnaise, and tomato ketchup, as well as salad dressings.
Gum arabic. Gum arabic is the dried, gummy exudate obtained from Acacia senegal and various other Acacia species. The exudation of gum arabic is a pathological condition attributed to unhealthy trees, as the gum is produced from breaks or wounds in the bark of the tree. Arabic was known over 4,000 years ago and is the most common and universally used of all of the natural gums.
Gum arabic is official in the U.S. Pharmacopeia (U.S. Pharmacopeial Convention, 1975) as well as the Food Chemicals Codex (Natl. Acad. Sci.-Natl. Res. Council, 1972). It is on the GRAS (generally recognized as safe) list under the Federal Food, Drug, and Cosmetic Act.
Gum arabic is a neutral or slightly acidic salt of a complex polysaccharide containing calcium, magnesium, and potassium ions. The main molecular structure is a chain of .beta.-galactopyranose units with some substitution at the C-6 position with various side chains.
Gum arabic is the most widely used of all the plant hydrocolloids. It is compatible with other gums, proteins, carbohydrates, and starches. It is commonly employed at a level of 2 lb/gallon of emulsion. It also serves to stabilize foams in the manufacture of soft drinks and beer. About 3 lb is enough to stabilize 50 barrels of beer. Gum arabic is also used in dairy products such as ices, sherbets, and ice creams. Here it functions to retard both ice crystal formation and growth.
Gum arabic is widely used in the candy industry. The gum is used to emulsify fats and retard sugar crystallization. It is used as a glaze in candy products and as a component of chewing gum, cough drops, and candy lozenges. Lozenges are also prepared from gum arabic by mixing finely ground or powdered sugar with a thick mucilage of gum arabic. Dietetic or sugarless hard candy drops and jujubes can be prepared from combinations of gum arabic, sorbitol, and mannitol. Arabic at a level of 1-3% will give a hard candy, 5-35% a medium center, and a soft drop can be obtained utilizing approximately 70% gum. The greater the percentage of arabic, the softer and more chewable the candy. An excellent glaze for marzipan and buns, gum arabic also acts as a protective coating in panned confectionery goods, and may be used in coating nuts. Gum arabic also improves the baking properties of rye and wheat flour at levels as little as 0.015%. The gum extends the shelf-life of bread by rendering it softer. It truly has universal applications.
Pectin. Food-grade pectin consists of partially methylated polygalacturonic acid units and is normally classified according to its degree of esterification or methoxyl content.
In high ester or high methoxyl (HM) pectin, a relatively high portion of the carboxyl groups occur as methyl ester and the remaining carboxylic acid groups are in the form of the free acid or as its ammonium, potassium, calcium, or sodium salt. Pectin in which less than 50% of the available carboxyl acid groups occur as the methyl ester is normally referred to as low methoxyl (LM) pectin. In general, LM pectin is obtained from HM pectin by a treatment such as mild acid or alkaline conditions. Amidated pectin is obtained from HM pectin when ammonia is used in the alkaline deesterification process. In this type of pectin, some of the remaining carboxylic acid groups have been transformed into the acid amide. Commercial soluble fibers are normally blended with sugars for standardization purposes, and some types may contain suitable food-grade buffer salts required for pH control and desirable setting characteristics.
Since it is a constituent of all plants, soluble fiber has long been part of the human diet. Pectin has been evaluated and cleared toxicologically by the Joint FAO/WHO Expert Committee on Food Additives. National and international food regulations recognize that pectin is a valuable food gelling agent and harmless food additive. Pectin is included in the list of permitted additives in standardized foods when a technological need can be proven.
Soluble fiber has been shown to be an effective hypocholesterolemic agent with minimal side effects (Reiser 1987! Food Technol. 31-91). It has also been found that grapefruit pectin inhibits hypercholesterolemia and atherosclerosis in miniature swine (Baekey et al. 1988! Clin. Cardiology 11:595-600). Furthermore, grapefruit pectin has proved to lower plasma cholesterol in human volunteers who were hypercholesterolemic, and to improve the ratio of low density lipoprotein cholesterol (LDLC) to high density lipoprotein cholesterol (HDLC) (Cerda 1988! Clin. Cardiology 11:589-594).
U.S. Pat. No. 4,497,838 describes the preparation of various orange products from orange peels. The preparation involves extraction of orange peels with a non-aqueous water-miscible solvent. The solvent-extracted peel is dried to produce a product high in cellulose and pectin.
Simple methods which allow the manufacture of soluble fiber food compositions are needed to provide the general public with dietary forms of soluble fiber. The present invention provides a preparation method which achieves this goal.